Mycobacterium tuberculosis sRNA

{{DISPLAYTITLE:Mycobacterium tuberculosis sRNA}}

File:B55 SScons.png of b55, one of the sRNAs experimentally confirmed in M. tuberculosis]]

Mycobacterium tuberculosis contains at least nine small RNA families in its genome.{{cite journal | vauthors = Arnvig KB, Young DB | title = Identification of small RNAs in Mycobacterium tuberculosis | journal = Molecular Microbiology | volume = 73 | issue = 3 | pages = 397–408 | date = August 2009 | pmid = 19555452 | pmc = 2764107 | doi = 10.1111/j.1365-2958.2009.06777.x }} The small RNA (sRNA) families were identified through RNomics – the direct analysis of RNA molecules isolated from cultures of Mycobacterium tuberculosis.{{cite journal | vauthors = Vogel J, Bartels V, Tang TH, Churakov G, Slagter-Jäger JG, Hüttenhofer A, Wagner EG | title = RNomics in Escherichia coli detects new sRNA species and indicates parallel transcriptional output in bacteria | journal = Nucleic Acids Research | volume = 31 | issue = 22 | pages = 6435–6443 | date = November 2003 | pmid = 14602901 | pmc = 275561 | doi = 10.1093/nar/gkg867 }}{{cite journal | vauthors = Kawano M, Reynolds AA, Miranda-Rios J, Storz G | title = Detection of 5′- and 3′-UTR-derived small RNAs and cis-encoded antisense RNAs in Escherichia coli | journal = Nucleic Acids Research | volume = 33 | issue = 3 | pages = 1040–1050 | year = 2005 | pmid = 15718303 | pmc = 549416 | doi = 10.1093/nar/gki256 }} The sRNAs were characterised through RACE mapping and Northern blot experiments. Secondary structures of the sRNAs were predicted using Mfold.{{cite journal | vauthors = Zuker M | title = Mfold web server for nucleic acid folding and hybridization prediction | journal = Nucleic Acids Research | volume = 31 | issue = 13 | pages = 3406–3415 | date = July 2003 | pmid = 12824337 | pmc = 169194 | doi = 10.1093/nar/gkg595 }}

sRNAPredict2 – a bioinformatics tool – suggested 56 putative sRNAs in M. tuberculosis, though these have yet to be verified experimentally.{{cite journal | vauthors = Livny J, Brencic A, Lory S, Waldor MK | title = Identification of 17 Pseudomonas aeruginosa sRNAs and prediction of sRNA-encoding genes in 10 diverse pathogens using the bioinformatic tool sRNAPredict2 | journal = Nucleic Acids Research | volume = 34 | issue = 12 | pages = 3484–3493 | year = 2006 | pmid = 16870723 | pmc = 1524904 | doi = 10.1093/nar/gkl453 }} Hfq protein homologues have yet to be found in M. tuberculosis;{{cite journal | vauthors = Sun X, Zhulin I, Wartell RM | title = Predicted structure and phyletic distribution of the RNA-binding protein Hfq | journal = Nucleic Acids Research | volume = 30 | issue = 17 | pages = 3662–3671 | date = September 2002 | pmid = 12202750 | pmc = 137430 | doi = 10.1093/nar/gkf508 }} an alternative pathway – potentially involving conserved C-rich motifs – has been theorised to enable trans-acting sRNA functionality.

sRNAs were shown to have important physiological roles in M. tuberculosis. Overexpression of G2 sRNA, for example, prevented growth of M. tuberculosis and greatly reduced the growth of M. smegmatis; ASdes sRNA is thought to be a cis-acting regulator of a fatty acid desaturase (desA2) while ASpks is found with the open reading frame for Polyketide synthase-12 (pks12) and is an antisense regulator of pks12 mRNA.

The sRNA ncrMT1302 was found to be flanked by the MT1302 and MT1303 open reading frames. MT1302 encodes an adenylyl cyclase that converts ATP to cAMP, the expression of ncrMT1302 is regulated by cAMP and pH.{{cite journal | vauthors = Pelly S, Bishai WR, Lamichhane G | title = A screen for non-coding RNA in Mycobacterium tuberculosis reveals a cAMP-responsive RNA that is expressed during infection | journal = Gene | volume = 500 | issue = 1 | pages = 85–92 | date = May 2012 | pmid = 22446041 | pmc = 3340464 | doi = 10.1016/j.gene.2012.03.044 }}

Mcr7 sRNA encoded by the mcr7 gene modulates translation of the {{not a typo|tatC}} mRNA and impacts the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus.{{cite journal | vauthors = Solans L, Gonzalo-Asensio J, Sala C, Benjak A, Uplekar S, Rougemont J, Guilhot C, Malaga W, Martín C, Cole ST | title = The PhoP-dependent ncRNA Mcr7 modulates the TAT secretion system in Mycobacterium tuberculosis | journal = PLOS Pathogens | volume = 10 | issue = 5 | pages = e1004183 | date = May 2014 | pmid = 24874799 | pmc = 4038636 | doi = 10.1371/journal.ppat.1004183 | doi-access = free }}

npcTB_6715 is a first sRNA identified as a potential biomarker for the detection of MTB in patients.{{cite journal | vauthors = Kanniappan P, Ahmed SA, Rajasekaram G, Marimuthu C, Ch'ng ES, Lee LP, Raabe CA, Rozhdestvensky TS, Tang TH | title = RNomic identification and evaluation of npcTB_6715, a non-protein-coding RNA gene as a potential biomarker for the detection of Mycobacterium tuberculosis | journal = Journal of Cellular and Molecular Medicine | volume = 21 | issue = 10 | pages = 2276–2283 | date = October 2017 | pmid = 28756649 | pmc = 5618688 | doi = 10.1111/jcmm.13148 }}